Now that the students have studied blood type identification, one can also study how urine can contain relevant information or clues to a criminal investigation. The synthetic urine that you will make allows the students to perform eight different tests. Each of these tests will provide possible clues for the investigator. This activity is different from all other activities to date because many of the results will provide inferences or clues rather than a direct result. The students will have to evaluate the relevance of the data in the context of the situation.
Part 1 - Initial Examination of Urine
Students make a visual examination of the odour and colour of the of the sample. While the urine is synthetic, it may take some time for students to "settle down" with the idea of working with urine. It is important for them to consider the samples as "real" and perform the procedures accordingly. This means, that they should keep their equipment clean and be aware of potential health concerns if they spill their samples.
Part 2 - Specific Gravity of Urine
Some time may be needed to show the class the proper use of a hydrometer and how it is used to determine specific gravity. Students should understand that having a change in the specific gravity of urine could indicate and medical problem.
Part 3 - pH of Urine
pH paper is used to determine the pH of urine.
Part 4 - Sediment Analysis
Analysis of sediment can provide clues such as an abnormal condition of blood in the urine or the presence of crystals in the urine that may indicate drug use. Students are provided with diagrams to assist in identification.
Part 5 - Presence of Albumin (protein)
Using part of the supernatant, students heat the liquid. If protein is present it will denature and make the solution cloudy.
Part 6 - Presence of Glucose
Testing for sugar may give an indication of diseases such as diabetes. Students will need to use care when working with Benedicts solution and a hot plate.
Part 7 - Unknown Sample Analysis
Students are given a choice of four samples to choose from and they are to determine the composition of the urine by performing the eight tests. Each sample has a different set of conditions based on how you prepare the sample. You may choose to make up your own samples or you may choose to follow the sample preparation key.
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